This invention relates to oral compositions comprising an amino compound, typically, an antiplasmin agent such as tranexamic acid and .epsilon.-aminocaproic acid, and a compatible aldehyde flavor.
It is well known in the art to blend an antiplasmin agent such as tranexamic acid and .epsilon.-aminocaproic acid in oral compositions. However, the use of an antiplasmin agent introduced a problem of discoloration of oral compositions as disclosed in Japanese Patent Publication No. 55-5484 and U.S. Pat. No. 4,272,513. This discoloration of antiplasmin agent-containing oral compositions is allegedly attributable to reaction of the antiplasmin agent with an aldehyde group in the coexisting flavor. To avoid discoloration, Japanese Patent Publication No. 55-5484 proposes to blend cyclodextrin in antiplasmin agent-containing oral compositions, and U.S. Pat. No. 4,272,513 proposes the use of a flavor substantially free of an aldehyde group.
It was fully anticipated that when antiplasmin agents such as tranexamic acid and .epsilon.-aminocaproic acid and other amino compounds were blended in oral compositions, the amino group would react with an aldehyde group in aldehyde type flavors to form a Schiff base which would cause the oral compositions to be colored or discolored. Particularly when either of the amino compound and the aldehyde flavor is an aryl compound, a stable Schiff base would be formed.
Making a number of experiments using various combinations of amino compounds and aldehyde compounds, the inventors have found that while acetaldehyde, cinnamic aldehyde, t-2-hexanal and the like cause amino compound-containing oral compositions to be colored or discolored, there are certain aldehyde flavors which are compatible with amino compounds. That is, amino compound-containing oral compositions are not colored or discolored when particular compatible aldehyde flavors are blended therein. Particularly, although chain hydrocarbon aldehyde flavors having a double bond between the .alpha.- and .beta.-positions with respect to the aldehyde group cause coloring or discoloration of amino compound-containing oral compositions, unexpectedly those cyclic aldhyde compounds having the structure ##STR1## wherein the ##STR2## moiety constitutes a segment of the cyclic structure have been found to cause no coloring or discoloration of amino compound-containing oral compositions as long as the compounds are free of a phenolic hydroxyl group. That is, substituted or unsubstituted, phenolic hydroxyl-free cyclic aldehyde compounds having an aldehyde group attached to one of their cyclically concatenating carbon atoms have been found useful as the compatible aldehyde flavors. It has also been found that aliphatic aldehyde compounds having 4 to 7 and 9 to 16 carbon atoms and free of a double bond between the carbon atoms at the .alpha.- and .beta.-positions with respect to their aldehyde group are useful as the compatible aldehyde flavors.